Going for a Ride
As people have broken up pastures and meadows into farms, grasslands have become more fragmented. That means that livestock can no longer easily transport seeds around the landscape. But since many grasslands are close to roads, the authors reasoned, perhaps cars could play the same role.
The team visited seven grasslands in southern Sweden and collected 31 samples of livestock manure and 48 samples of dirt on farm vehicles, including cars, vans, and tractors. Then the researchers observed which types of seedlings grew from the samples in a greenhouse.
The manure yielded 31,793 seedlings from 108 species, and the vehicle mud yielded 12,618 seedlings from 110 species, the team reports in Ecography. The vehicles had picked up seeds from 69 of the same species as livestock, and both the vehicle dirt and manure tended to contain small seeds from short plant species.
The team also found seeds of four invasive species in the vehicle mud, but those plants had already taken root in Sweden before cars were invented. “[M]otor vehicles have the potential to provide connectivity for otherwise dispersal limited species between fragmented grasslands,” the authors conclude. — Roberta Kwok | 25 April 2013
Source: Auffret, A.G. and S.A.O. Cousins. 2013. Grassland connectivity by motor vehicles and grazing livestock. Ecography doi: 10.1111/j.1600-0587.2013.00185.x.
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